Regenerative electromechanical frequency selective apparatus



Dec. 26, 1939. w, SQLLER 2,184,321

REGENERATIVE ELECTROMECHANICAL FREQUENCY SELECTIVE APPARATUS Filed Aug. 21, 1937 2 She'ets-Sheet 1 g Wa U240 50m,

INVENTOR.

BY d ATTORNEY 3 Dec. 26, 1939. I w, SQLLER 2,184,321

REGENERATIVE ELECTROMECHANICAL FREQUENCY SELECTIVE APPARATUS Filed Aug. 21, 1937 2 Sheets-Sheet 2 IN V EN TOR.

ATQTORNEY Patented Dec. 26, 1939 g 4 2,184,321

NITED STATES PATENT OFFICE REGENERATIVE ELECTROMECHANICAL FREQUENCY SELECTIVE APPARATUS Walter Soller, Cincinnati, Ohio, assignor of onehalf to William H. Woodin, Jr., Tuscon, Ariz.

Application August 21, 1937, Serial No. 160,331

18 Claims. (01. 178-31) My invention relates broadly to multiplex elecon line 3-3 of Fig. 2, with parts broken away; trical transmission systems and more particular- Fig. 4 is a foreshortened horizontal sectional view ly to highly selective frequency separating retaken substantially on line 4-4 of Fig. 2, with ceiving apparatus of the electromechanical type. parts broken away; Fig. 5 is an enlarged per- This application is a continuation in part of spective view of the coil structure forming a secg my copending application Serial No. 4,393, filed tion of the torsional pendulum device of my in- January 31, 1935, for Television system. vention; Fig. 6 is an enlarged elevation of a por- One of the objects of my invention is to protion of the supporting structure for the torsional vide frequency selective apparatus for use in conpendulums showing one form of individual tuning junction with television systems of my invention means which may be employed in connection 10 such as are disclosed in my copending applicawith the torsional pendulums; Fig. 7 is a horizontions Serial No. 733,300, filed June 30, 1934, for tal sectional view taken on line 1-1 of Fig. 6; Television system, and Serial No. 4,393, filed Jan- Fig. 8 is a cross-sectional View taken on line nary 31, 1935, for Television system. 88 of Fig. 6, with a portion broken away and Another object of my invention is to provide shown in section; and Fig. 9 is an enlarged per- 16 electromechanical frequency selective apparatus spective view of the tuning device shown in operinvolving regenerative principles for increasing ative positions in Figs. 2, 3 and 6--8.

the selectivity of the apparatus. In the following specification, I shall describe Stillanother object of my invention is to promy invention particularly as employed in telegg vide a construction of electromechanical frevision systems of the type involving the trans-v quency selective apparatus which is compact and mission simultaneously of a plurality of modulathighly eflicient in operation and thus adaptable ed carried currents of audible or super-audible to the separation of a large number of frequencies frequency with frequency differences of only 3. within a limited frequency band with the difierfew cycles, but it will be understood that the ence in frequency between adjacent waves in the apparatus .may be employed in any multiplex order of a few cycles. system where highly selective frequency separa- A further object of my invention is to provide tion is required. a system of tuned torsional pendulum devices In television systems of the type described a each having a pair of coils mounted for oscillaseparate carrier, or sub-carrier current is em- 3@ tion in separate magnetic fields, one of the coils ployed for each line of the object transmitted, operating as a motive coil and the other as a t and these currents, simultaneously modulated by generative coil, with connections between the the light intensities on corresponding portions coils f rmin a r n r tive ystem. of the object, are transmitted at the same time A still further object of my invention is to to receiving apparatus where the problem is preprovide a system of tuned torsionalpendulum desented of separation and reproduction. Herevices with coils connected in a. regenerative cirtofore, the frequency separation has been effectcuit, as above stated, and means in the electrical ed at the receiver by electrically resonant circuits circuit tuned to resonance with the frequency of or electromechsanical apparatus of relatively the torsional pendulum. broad selective characteristics. Where a large Still anot Object of y invention s to P O- number of carrier currents are employed, as is vide a system of torsional pendulum devices with necessary to obtain finer definition in the picture coils connected in a regenerative circuit, as above produced, smaller frequency separation between stated, and means individual to each device for the currents is desirable in order to limit the fretnning the respective device for mechanical Oscilquency band required for the transmission therelation at aselected frequency. of; The use of electromechanical selective ap- Other and further objects of my invention reparatus reduces the band width by permitting a side in the structure and arrangement of the decrease in the frequencies employed to values apparatus as hereinafter described, with refereven within the audible range. At the same time ence to the accompanying drawings, in which: some decrease in the frequency separation is pos- Figure 1 is a schematic diagram of the circuit sible. By employing the regenerative electro- 59 connections in a multiplex receiver employing mechanical apparatus of my invention, further the apparatus of my invention; Fig. 2 is a verreduction in the frequency separation is postical sectional view of the apparatus of my insible. resulting in a further decrease of the frevention, on line 2-2 of Fig. 3; Fig. 3 is a partial 'quency band required for the transmission of a longitudinal vertical sectional view substantially given number of currents.

Referring to the drawings in more detail, the circuit arrangement shown in Fig. 1 comprises an actuating coil I mounted for operation with respect to a magnetic core 2, which is energized with a magnetizing force from coil 3 connected with a direct current source 4 so asto provide optimum field strength at the poles of the core 2. C011 I is fed by the complex current having components of the different frequencies, through the input 0 terminals 5. Movable coils, generally designated at 6, are mounted in the magnetic field of the core 2 and energized inwnmon from a source of direct current, as at 7..

Referring now to Figs. 2-4, the elements above defined are designated by like reference characters. Core 2 is supported by angle members 8, 9, near the base of a frame structure Ill. Coils I and 3 are mounted on the core 2. An additional core member I2 is provided intermediate the poles gs of core 2 and is supported at each end of the frame structure Ill on non-magnetic bars It, which may be of insulating material or of metal such as brass. The movable coils, 6, are mounted, as shown more particularly in Fig. 5, within a frame of nonmagnetic metal such as brass, formed of two bent strips I5 and I6, secured together by rivets I1, or in any suitable manner. The lower ends of the strips I5 and I6 are secured between angle members I8 and I9 which are supported by cross bars so at either end of the frame structure I0.

The upper portions of each pair of strip members I5 and I6 are bent to form a second frame for mounting another coil, one of a second group designated generally at 20, and the upper ends of :5 the strip members are secured between angle members 23 and 24 in a manner similar to the lower ends and with the strip members held taut. As thus mounted, and when energized together with coils I and 3 as indicated in Fig. 1, coils 6 40 will oscillate at individual frequencies dependent upon the natural periods of oscillation of the torsional pendulums thus provided, and act as motive means for correspondingly oscillating coils 20, as will hereinafter be more fully considered.

In order to determine accurately the natural frequency of oscillation of each torsional pendulum device, a slidable clamp 25 is provided on each device. The clamp comprises an apertured body portion 25a closely accommodating strips I5 and I6, and a pair of oppositely disposed arm portions 251) and 250. Each pair of strip members I5, I6, is mounted in angle members l8, I8, and 23, 24, in spaced relation as shown more clearly in Figs. 6 and 7, and the arm portions 25b and 250 55 of clamp 25 are adapted to enter the space between the angle members 23 and 24, adjacent the sides of the respective pair of strip members I5, I6. The clamp 26 is slidable on the respective pair of strip members, with the arm portions re- 50 tained between the angle members, for adjusting the effective length of the oscillating portion of the torsional pendulum device, and thus determining its natural period of oscillation and frequency. Clamp 25 includes the bolt 26 for se- 5 curing it in adjusted position. Other means,

such as a spiral spring. may be employed for adjusting the responsive frequency of the torsional pendulum devices without departing from the basic principles of my invention.

70 Coils 20 are mounted between the poles of core structure 2| similar to the core 2 andsupported by angle members 28, 29, in the frame structure II). An additional core member 21 is provided intermediate the poles of core 21 and is supported,

1 like the core member I2, at each end of the frame structure It on non-magnetic cross bars. Core members I2 and 27 pass through the respective groups of coils 6 and 20 and more particularly serve as core members therefor. Energizing coils 30 are mounted on core 2 I. I5 Referring again to Fig. 1, coils 36 are shown energized from a source 3i of direct current to provide a constant magnetic field about coils 28, which, being oscillated by the respective coils 6, have induced therein a voltage of corresponding is frequency and of magnitude proportional to the amplitude of oscillation. As shown in Fig. 1, this voltage is fed back to the respective coils 8, through condensers 32, 32, 32" which serve as blocking condensers to the voltage of source I 16 and also are chosen of such value in each circuit as to render the combination of the respective coils 6 and 20 with the respective condenser electrically resonant at the frequency of the torsional pendulum device supporting the coils. Each of the 80 coils 6 therefore receives an additional voltage similar to the signal energy selected from the complex magnetic field produced by coil I, and the amplitude of oscillation of coils 6 and coils 20 is increased, at the selective frequency, with a 85 corresponding increase in the voltage generated in the coils 20. The cycle of regeneration is repetitive up to a predetermined limit, dependent upon the electrical and physical characteristics of the circuit. The oscillation is substantially stable 30 at the selective frequency and the amplitude of oscillation varies in accbrdance with the modulation of the corresponding carrier current. The output of the system may be taken from coils 20.

'In this circuit illustrated in Fig. 1, I have shown 35 the output of the frequency selective apparatus connected with a multi-unit electron tube 34 of the type disclosed in my copending application Serial No. 4,393, supra. The tube 34 comprises a single cathode electrode 35, a single screen grid electrode 36, and corresponding pluralities of control grid and anode electrodes, indicated generally at 31 and 38 respectively. One terminal of each of the coils 20 is connected in common to the cathode 35 through conductor 39 and a source of bias potential 40; the other terminals of the coils 20 being separately connected with the grid electrodes 31. The output of the tube 34 is taken from the several anode electrodes 38, and from the cathode 35. A source of potential connected at M supplies potential to all the anodes 38, and also a potential for the screen grid 36 through potential divider 42. In a television system, the output of tube 34 connects with picture producing apparatus.

In order to adjust the positions of the coils 20, each coil is connected through a separate adjustable resistor 43, 43', 43" to a source of direct current at 45, and by variation of the polarizing current in the respective coils the normal positions of the coils with respect to the core assembly 2I, 21, may be determined. With no current flowing in actuating coil I, these positions are preferably the zero positions shown in the drawings in Figs. 2-4. :5

As the coil I creates an alternating flux, core 2 and core member I2 are laminated to reduce energy loss. Core 2I is shown laminated, and core member 21 may also be laminated, if desired, to reduce inductive eddy current losses which may be caused by proximity to the lower magnetic structure.

While I have described my invention in a certain preferred embodiment I do not intend to be limited thereby, and I desire it understood that modifications may be made and that no limitations upon my invention are intended except as may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. Electromechanical frequency selective apparatus comprising electromagnetic frequency responsive motive means, electromagnetic generative means mechanically connected with and driven by said motive means, and electrical feedback connections from said generative means to said motive means.

2. Electromechanical frequency selective apparatus comprising electromagnetic frequency responsive motive means, and means mechanically driven by said motive means and electrically connected therewith for producing regenerative action through said motive means.

3. Electromechanical frequency selective apparatus comprising electromagnetic frequency responsive motive means, electromagnetic generative means driven by said motive means, and

connections from said generative means to said motive means including means for tuning the electrical circuit formed by said connections to the frequency of said electromagnetic frequency responsive motive means.

4. Electromechanical frequency selective apparatus comprising electromagnetic frequency responsive means including electromagnetic motive means; and electromagnetic generative means mechanically driven by said motive means and electrically connected with said motive means for regenerative action through said mo- I tive means and said generative means.

5. Electromechanical frequency selective apparatus comprising electromagnetic frequency responsive means including electromagnetic motive means constituted as a torsional pendulum device, electromagnetic generative means driven by said motive means, and connectionsfrom said generative means to said motive means including means for tuning the electrical circuit formed by said connections to the natural frequency of oscillation of said torsional pendulum device.

6. In a multiplex carrier current transmission system, electromechanical frequency selective apparatus operative in a complex magnetic field including components derived from the several carrier currents, comprising a plurality of electromagnetic frequency responsive devices each being constituted as a torsional pendulum, and means for mechanically adjusting each of said devices for oscillation at a frequency corresponding to the frequency of one of said carrier currents and for responding to the component of said magnetic field derived therefrom.

7. In a multiplex carrier current transmission system, electromechanical frequency selective apparatus operative in a complex magnetic field including components derived from the several carrier currents, comprising a plurality of tuned electromagnetic frequency responsive motive de-.

vices, a corresponding plurality of electromagnetic generative means individually driven mechanically by a respective one of said motive devices, and electrical feed-back connections from each of the generative means to the respective motive device.

8. In a multiplex carrier current transmission system, electromechanical frequency selective apparatus operative in a complex magnetic field including components derived from the several carrier currents, comprising a plurality of tuned electromagnetic frequency responsive motive devices, a corresponding plurality of electromagnetic generative means individually driven by a a respective one of said motive devices; and connections from each of the generative means to the respective motive device including means for tuning the electrical circuit formed by said connections to the frequency of the respective electromagnetic frequency responsive device.

In a multiplex, carrier current transmission system, electromechanical frequency selective apparatus comprising a plurality of electromagnetic motive devices, and a corresponding plurality of electromagnetic generative means mechanically actuated respectively by said motive devices and electrically connected with the respective electromagnetic motive device for regenerative action through said device and said means.

10. Electromechanical frequency selective apparatus operative in a complex magnetic field including components derived from several currents of different frequencies, comprising a plurality of electromagnetic frequency responsive motive devices and a corresponding plurality of electromagnetic generative means mounted together'in respective pairs as torsional pendulum devices, means for producing'a constant magnetic field for said generative means, said motive devices being disposed in said complex magnetic field and said generative means in the constant magnetic field provided therefor, and electrical connections from said generative means to the respective motive devices for producing regenerative action.

11. Electromechanical frequency selective apparatus as set forth in claim 10 and including a source of direct current, and a circuit including a variable resistor connected from said source to each of said electromagnetic generative means for producing a variable magnetic field coactive with said constant magnetic field for determining the at rest position of the respective torsional pendulum device.

12. Electromechanical frequency selective apparatus as set forth in claim 10 and including manually adjustable means mounted on each of said torsional pendulum devices for varying the natural period of oscillation thereof and tuning said devices to respond to components of different predetermined frequencies in said complex magnetic field.

13. Electromechanical frequency selective apparatus including a torsional pendulum device formed of flat strip members secured at opposite ends between supporting bars, and means for varying the effective length of said strip members comprising a close-fitting sleeve member slidably mounted on said strip members adjacent one end thereof and having a pair of arm portions extending at opposite sides of said sleeve member parallel with the edges of said strip members and in contact with the supporting bar so as to prevent oscillatory movement of said sleeve member, and means for clamping said sleeve members in selected position.

14. Electromechanical frequency selective apparatus comprising electromagnetic frequency responsive motive means and electromagnetic generative means mounted together as a tor sional pendulum device, said motive means being disposed in a complex magnetic field, and re- -sponsive to components of a predetermined frequency, said generative means being disposed in a constant magnetic field, and electrical connecducing a complex signal current comprising a plurality of simultaneously modulated different frequency currents and a synchronizing current, electromechanical frequency separator apparatus comprising a frame structure, a laminated magnet core supported in said frame structure, a

main winding and field windings mounted on.

said laminated core, a plurality of vibratible elements fixed to said frame structure and having portions thereof disposed between the poles of saidlaminated core, said main winding conducting the modulated different frequency currents of said complex signal current, said vibratible elements being selectively responsive to said different frequencies, an electromagnet comprising a magnet core supported in said frame structure and field windings mounted on said core, a plurality of coils pivoted with respect to said frame structure and vibratible-in the field of said electromagnet, and means connecting said vibratible elements respectively with said vibratible coils whereby said coils are vibrated in the field of said electromagnet.

16. In a television receiving system for cooperation with a television transmitting system producing a complex signal current comprising a plurality of simultaneously modulated different frequency currents and a synchronizing current,

electromechanical frequency separator apparatus comprising a frame structure, a laminated magnet core supported in said frame structure, a main winding and field windings mounted on said laminated core, a plurality of vibratible elements fixed to said frame structure and having portions thereof disposed between the poles of said laminated core, said main winding conducting the modulated different frequency currents of said complex signal current, said vibratible elements being selectively responsive to said different frequencies, an electromagnet comprising a magnet core supported in said frame structure and field windings mounted on said core, a plurality of merger coils mounted'respectively in connection with said vibratible elements and disposed in the field of said electromagiiet whereby said coils are vibrated in said field under the control of said vibratible elements.

17. In a television receiving system for cooperation with a television transmitting system producing a complex signal current comprising a plurality of simultaneously modulated different frequency currents and a synchronizing current,

electromechanicalfrequency separator apparatus including a plurality of vibratible elements constituting means selectivelyresponsive to said difierent frequency currents, a frame structure, an electromagnet having a magnet core supported in said frame structure, pole faces on said core, a plurality of coils, means for mounting said coils in connection with said vibratible elements for vibratible movement between the pole faces of said core under the control of said vibratible elements, said'pole faces embracing said plurality of coils, the yoke of said magnet core being foreshortened, and a field winding mounted on said foreshortened yoke.

18. In a television receiving system for cooperation with a television transmitting system producing a complex signal current comprising a plurality of simultaneously modulated different frequency currents and a synchronizing current, electromechanical frequency separator apparatus including a plurality of vibratible elements constituting means selectively responsive to said different frequency currents, a frame structure, an electromagnet having a magnet core supported in said frame structure, pole faces on said core, an auxiliary coremember disposed between the pole faces of said magnet core with twin air gaps between said pole faces and said auxiliary core, a plurality of coils arranged coaxially with said auxiliary core member for vibratible vmovement in said twin air gaps under the control of said vibratible elements, and means for connecting said vibratible elements individually with said coils for supporting said coils in position in said twin air-gaps.

WALTER SOLLER. 

